Parse the column/field name correctly in reports

[jntullo]

BZ: https://bugzilla.redhat.com/show_bug.cgi?id=1402547

When creating a report, the field names were not being stored properly in col_options because of how the field was being parsed.

For example, the field Vm.miq_provision.miq_request-requester_name was being parsed as miq_request.v_approved_by instead of the correct miq_provision.miq_request.v_approved_by, causing the MiqExpression to never evaluate to true and therefore not styling the report correctly. This PR leverages a new function added to MiqExpression::Field to get the correct column name

Here are some gifs to display what was happening (sorry, they're a bit long):
Before:

After:

@miq-bot add_label cloud intel/reporting, wip, bug

[miq-bot]

Checked commit jntullo@c85cea2 with ruby 2.2.6, rubocop 0.47.1, and haml-lint 0.20.0
2 files checked, 0 offenses detected
Everything looks fine. 🍰

[jntullo]

@miq-bot assign @dclarizio
@miq-bot remove_label wip

dependent PR has been merged

[simaishi]

Fine backport details:

$ git log -1
commit a63c05d5d714ccdb62c819502074951dbdeb8873
Author: Dan Clarizio <[email protected]>
Date:   Wed Jun 7 13:35:37 2017 -0700

    Merge pull request #1170 from jntullo/bz/style_report_columns
    
    Parse the column/field name correctly in reports
    (cherry picked from commit 7da9572cb3b67d9b0e500725ae0a692cba212cec)
    
    https://bugzilla.redhat.com/show_bug.cgi?id=1460761

[simaishi]

Euwe backport (to manageiq repo) details:

$ git log -1
commit 0348a07798d19a67c167af3acd8f35c4e7f1c245
Author: Dan Clarizio <[email protected]>
Date:   Wed Jun 7 13:35:37 2017 -0700

    Merge pull request #1170 from jntullo/bz/style_report_columns
    
    Parse the column/field name correctly in reports
    (cherry picked from commit 7da9572cb3b67d9b0e500725ae0a692cba212cec)
    
    https://bugzilla.redhat.com/show_bug.cgi?id=1465079